SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '475c58ac88ac8cbbf2a087ece71c42cf4aba0e05feaff824c45705b947958ade' 
  AND token = 'TWAhBGPykmJhdh2K9anMibKBQjUjkRUB3uCVV+IK6CI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}